AT&T customers who’ve hung onto their unlimited data plans now have a lot more full-speed data to play with.

According to AT&T’s website (via DSLReports), users with legacy unlimited data plans can use up to 22GB of data per month without getting throttled. After that, users will see slower speeds in congested areas, with the degree of throttling depending on the amount of congestion. (Users will also get a warning when they’ve exceeded 16.5GB, which is 75 percent of 22GB.)

This is a major change from AT&T’s previous policy, which began throttling unlimited data users at 5GB in a congested area. In an even older policy, AT&T throttled users at just 3GB for 3G/4G HSPA+ networks and 5GB for 4G LTE networks, whether they were in a congested site or not. (Some users complained that throttling began at just 2GB.)

Why this matters: AT&T stopped offering unlimited data plans to new customers in 2012. While existing customers have been allowed to keep their unlimited data, AT&T has severely curtailed the benefits of those plans through strict throttling policies and the inability to tether a tablet or computer without additional fees. Subscribers who’ve stuck with their unlimited plans through it all are now being handsomely rewarded, especially as streaming video, photo sharing, and streaming music cause data use to climb.

Under pressure

AT&T says the data expansion is thanks to its network management practices, which have “continued to evolve over time to benefit our customers and take advantage of the billions we have spent to expand and augment our networks.”

What AT&T doesn’t readily acknowledge is that it’s been smacked by lawsuits from both the Federal Communications Commission and the Federal Trade Commission over its lack of disclosure about throttling. AT&T is now facing a $100 million fine from the FCC, while the FTC’s lawsuit is still ongoing.

It’s also worth noting that AT&T, like all wireless carriers, is now subject to the FCC’s net neutrality rules, which allows for reasonable network management, but only for “primarily technical” needs. Potentially, an unlimited plan with an artificially low data cap could run afoul of those rules.

AT&T’s new approach is similar to that of T-Mobile, which begins throttling unlimited data users at 21 GB. Sprint and Verizon don’t target heavy data users for throttling, though some Sprint plans have lower bandwidth priority than others.

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